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Objective:To evaluate the effect of hydrogen on the expression of hippocampal cold-inducible RNA-binding protein (CIRP) after cardiac arrest-resuscitation in rats.Methods:Ninety clean-grade healthy male Sprague-Dawley rats, weighing 280-320 g, were randomly divided into 3 groups: sham group (group Sham, n=20), cardiac arrest-cardiopulmonary resuscitation group (group CPR, n=35), and hydrogen-rich saline group (group H 2, n=35). Cardiac arrest was induced by transoesophageal cardiac pacing followed by CPR in group CPR.Only femoral arteriovenous puncture and tracheal intubation were performed in group Sham.Hydrogen-rich saline 5 ml/kg was intraperitoneally injected immediately after recovery of spontaneous circulation (ROSC) and at 6 and 12 h after ROSC in group H 2 , while the equal volume of normal saline was given instead in the other two groups.Neuro-functional deficit was assessed using neurologic deficit scores (NDS) at 1 and 3 days after ROSC.The animals were sacrificed immediately after intubation in group Sham and at 6 h and 1, 2 and 3 days after ROSC in CPR and H 2 groups, and the hippocampal tissues were obtained to detect the expression of nuclear and cytoplasmic CIRP by Western blot. Results:Compared with group Sham, NDS was significantly decreased at each time point after ROSC in group CPR and group H 2, the expression of nuclear CIRP was significantly down-regulated at 1, 2 and 3 days after ROSC, and the expression of cytoplasmic CIRP was up-regulated at 1 and 2 days after ROSC in group CPR, and the expression of nuclear CIRP was significantly down-regulated at each time point after ROSC, and the expression of cytoplasmic CIRP was down-regulated at 2 and 3 days after ROSC in group H 2 ( P<0.05). Compared with group CPR, NDS was significantly increased at each time point after ROSC, the expression of nuclear CIRP was down-regulated at 6 h after ROSC, and the expression of cytoplasmic CIRP was down-regulated at 1 and 2 days after ROSC in group H 2 ( P<0.05). Conclusion:The nechanism by which hydrogen reduces brain injury after cardiac arrest-resuscitation may be related to down-regulating hippocampal CIRP expression in rats.
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Objective To investigate the effect of mild hypothermia combined with mitochondrial divison inhibitor 1 in mitochondrial after cerebral ischemia-reperfusion (IR).Methods Fourty male healthy Sprague-Dawley (SD) rats, weighing 280-320 g, were randomly divided into 5 groups (n=8 each): group Sham, group IR, hypothermia group (group H), Mdivi-1 group (group M) and hypothermia+Mdivi-1 group (group HM).Animal models of global cerebral IR were established by transoesophageal cardiac pacing inducing cardiac arrest followed by cardiopulmonary resuscitation (ischemia 4 min and reperfusion 6 h).The group Sham was similarly treated to group IR except the cardiac arrest and cardiopulmonary resuscitation.In groups H and HM, the core temperature was cooled down to 32-34℃ within 15 min starting from the beginning of reperfusion, and maintained for 6 h.In the other groups, the core temperature was maintained at the normal temperature.In groups M and HM, the animals were given Mdivi-1 (1.2 mg/kg) intravenously at the beginning of the reperfusion and the other groups were given the same Volume of dimethylsnlfone (DMSO).After 6 h of reperfusion, the rats were sacrificed, and bilateral hippocampi were immediately removed for determination the protein level of dynamin-related proten 1 (Drp1) and cytochrome C (Cyt-C) expression by Western blot and obsevation of the mitochondrial structure of pyramidal cell in hippocampal CA1 under electronic microscope.Results Compared with group Sham, the expression of Drp1 and Cyt-C was up-regulated in groups IR, H, M and HM (P＜0.05).Compared with group IR, the expression of Drp1 and Cyt-C was down-regulated in groups H, M and HM (P＜0.05).Compared with groups H and M, the expression of Drp1 and Cyt-C was down-regulated in group HM (P＜0.05).There was no significant difference in the expression of Drp1 and Cyt-C between groups H and M.The mitochondria were rod-shaped with clear and sound structure in group Sham, while mitochondria showed various degree of fission, swollen structures, matrix deposit, vacuoles formation and cristae collapse in other groups.The changes of group HM were relatively slight.Conclusion Mild hypothermia combined with mitochondrial divison inhibitor 1 alleviate mitochondrial damage after global cerebral IR of rats.The combined effect is better than that of any individual application.
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Objective To evaluate the effect of hypothermia on the expression of dynamin?related protein 1 ( Drp1) in brain tissues during global cerebral ischemia?reperfusion ( I∕R) in rats. Methods Thirty?six healthy male Sprague?Dawley rats, weighing 280-320 g, were divided into 3 groups ( n=12 each) using a random number table: sham operation group ( group Sham ) , global cerebral I∕R group ( group I∕R) and hypothermia group ( group H) . Cardiac arrest was induced by transoesophageal cardiac pacing followed by cardiopulmonary resuscitation to establish the global cerebral I∕R model in anesthetized rats in I∕R and H groups. In group H, the body temperature ( rectal temperature) was cooled down to 32-34 ℃ within 15 min starting from the beginning of reperfusion, and maintained at this level for 6 h. At 72 h of reperfusion, neurological deficit was scored, and the rats were sacrificed, and the whole brain was removed for examination of the pathological changes in hippocampal CA1 region and for determination of nor?mal pyramidal cell count and neuronal apoptosis in hippocampal CA1 region and expression of Drp1 and cy?tochrome c (Cyt c) in hippocampal tissues (by Western blot). The apoptosis rate was calculated. Re?sults Compared with group S, the neurological deficit score and apoptosis rate were significantly in?creased, and the number of normal pyramidal cells was decreased in I∕R and H groups, the expression of Drp1 and Cyt c in hippocampal tissues was significantly up?regulated in group I∕R ( P0.05) . Compared with group I∕R, the neurological deficit score and apoptosis rate were significantly de?creased, the number of normal pyramidal cells was increased, and the expression of Drp1 and Cyt c in hip?pocampal tissues was down?regulated in group H ( P<0.05) . Conclusion The mechanism by which hypo?thermia inhibits cell apoptosis during global cerebral I∕R may be related to down?regulation of Drp1 expres?sion in rats.
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ObjectiveTo evaluate the effect of hydrogen-rich saline given during reperfusion on global cerebral ischeraia-reperfusion (I/R) injury in rats.Methods Seventy-two adult male SD rats,aged 2.0-2.5 months,weighing 260-300 g,were randomly divided into 3 groups (n ＝ 24 each):sham operation group (group S),group I/R and hydrogen-rich saline group (group H).In groups I/R and H cerebral I/R was induced by occlusion of 4 vessels( cauterization of bilateral carotid arteries and 15 min occlusion of bilateral common carotid arteries).In group H intraperitoneal 0.6 mmol/L hydrogen-rich saline 5 ml/kg was injected at 6 h of reperfusion,while equal volume of normal saline was injected instead of hydrogen-rich saline.Eighteen rats of each group were sacririced at 24 h of reperfusion,and then the hippocampi were removed for determination of malondialdehyde (MDA),tumor necrosis factor-α (TNF-α),interleukin-6 (IL-6)contents,and nuclear factor-κB (NF-κB) activity and activated caspase-3 expression.Another six rats of each group were sacrificed at 72 h of reperfusion,and then brain tissues were removed for microscopic examination and counting the number of uninjured pyramidal cells in hippocampal CA1 region.ResultsCompared with S group,the contents of MDA,TNF-α,IL-6 and NF-κB activity were significantly increased,activated caspase-3 expression was significantly up-regulated,uninjured pyramidal cells in hippocampal CA1 region were significantly decreased in I/R group( P < 0.05).Hydrogen-rich saline given during reperfusion attenuated the above-mentioned I/R-induced changes( P < 0.05 ).The histologic damage of the hippocampal CA1 region was significantly slighter in group H than group I/R.ConclusionHydrogen-rich saline given during reperfusion can reduce global cerebral I/R injury in rats through inhibition of lipid peroxidation,inflammatory response and apoptosis.
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Objective To investigate the role of mitochondrial permeability transition pore (mPTP) of hippocampal neurons in process of hydrogen-rich saline attenuating global cerebral ischemia-reperfusion (I/R) injury in rats.Methods Seventy-two male Sprague Dawley rats,weighing 250-300 g,were randomly divided into six groups ( n =12 each):sham operation group (group S),cerebral ischemia-reperfusion group (group IR),normal saline group (group NS),hydrogen-rich saline group (group H),atractyloside group (group A) and hydrogen-rich saline + atractyloside group (group HA).Global cerebral I/R injury was produced by four-vessel occlusion method.Bilateral vertebral arteries were cauterized.Then bilateral common carotid arteries were occluded for 15min and followed by reperfusion.In groups H and HA,hydrogen-rich saline 5 ml/kg was injected intraperitoneally immediately after reperfusion,while equal volume of normal saline was injected in the other four groups.The rats in groups A and HA received intracerebroventricular injection of atractyloside 15 μl 10 min before reperfusion,while groups NS and H received intracerebroventricular injection of equal volume of normal saline.After the neurological behavior was evaluated at 24 h of reperfusion,8 rats in each group were sacrificed and the hippocampi were immediately isolated and homogenized followed by density gradient centrifugation.The opening degree of mPTP was assayed with spectrophotometry and the mitochondrial membrane potential (MMP) was detected with Rhodamine 123 method.Four rats in each group were killed at 72 h of reperfusion and the brains were removed for microscopic examination of the area CA1 of the hippocampus and determination of the number of normal pyramidal neurons.Results Compared with group S,the neurological behavior was compromised,MMP was decreased and mPTP opening degree was enhanced in the other five groups ( P ＜ 0.05).The neurological behavior was better,MMP was increased and mPTP opening degree was decreased in groups H and HA as compared with group IR ( P ＜ 0.05).Compared with group H,the neurological behavior was compromised,MMP was decreased and mPTP opening degree was enhanced in group HA ( P ＜ 0.05).Compared with group IR,the number of normal pyramidal neurons at 72 h of reperfusion in the CA1 region of the hippocampus was higher in group HA ( P ＜0.05).The injury of the CA1 region of the hippocampus at 72 h of reperfusion was attenuated in group H as compared with groups IR,NS,A and HA.Conclusion Hydrogen-rich saline can attenuate global cerebral I/R injury throngh inhibiting the mPTP opening and reducing the dissipation of MMP,thus maintaining the mitochondrial function.
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Objective To investigate the effect of hydrogen-rich saline combined with mild hypothermia on cerebral ischemia-reperfusion (IR) injury in rats. Methods Fifty male SD rats, aged 9-10 weeks, weiging 250-300 g, were randomly divided into 5 groups (n= 10 each): sham operation group (group S), group IR, hygrogen-rich saline group (group H), mild hypothermia group (group M) and hydrogen-rich saline + mild hypothermia group (group HM). In group IR, H, M and HM cerebral IR was induced by 15 min ligation of bilateral carotid artery followed by 6 h reperfusion. In group H and HM intraperitoneal hydrogen-rich saline 5 ml/kg was injected immediately after reperfusion, while the equal volume of normal saline was injected instead of hydrogen-rich saline in the other three groups. At the same time, the rectal temperature was maintained at 37-38 ℃ in group S,IR and M, while it was reduced to 32-34 ℃ by physical method within 15 min, lasting for 6 h, in group M and HM. The animals were sacrificed after 6 h of reperfusion, and then the hippocampus was removed for microscopic examination. The expression of HO-1 and content of MDA and TNF-α were determined by Western blot. Results The cerebral IR injury was attenuated in group H, M and HM compared with group IR, with the slightest injury in group HM. The expression of HO-1 and content of MDA and TNF-α were significantly higher in group IR, H, M and HM than in group S. The expression of HO-1 was significantly higher, while the content of MDA and TNF-α were lower in group H, M and HM than in group IR, and in group HM than in group H and M. There was no significant difference in the expression of HO-1 and content of MDA and TNF-α between group H and M. Conclusion Hydrogen-rich saline combined with mild hypothermia can attenuate cerebral I/R injury in rats via up-regulating the expression of HO-1 and decreasing the content of MDA and TNF-α in hippocampus.
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Objective To explore the possible mechanism for the neuroprotective effect of ifenprodil by investigating its effects on inducible nitric oxide synthase (iNOS) expression and activity and apoptosis in the ischemic penumbra following focal cerebral ischemia-reperfusion (I/R) in rats.Methods Fifty-four adult male SD rats weighing 280-320 g were randomly divided into 3 groups ( n = 18 each) : I sham operation group (group S) ; II focal cerebral I/R group (group I/R) and Ⅲ ifenpradil preconditioning group (group IF) received intraperitoneal ifenprodil 10 mg/kg before focal cerebral I/R. Focal cerebral I/R was induced by middle cerebral artery occlusion (MCAO) . A 3-0 nylon thread with rounded tip was inserted into right internal jugular vein and threaded cranially until resistance was met. MCAO was maintained for 2 h. At 48 h after reperfusion, the animals were assessed for neurological function which was scored (0 = no functional deficit, 4 = unable to crawl, unconscious) and then decapitated. The brains were immediately removed for microscopic examination and determination of iNOS protein expression and activity, NO content and apoptosis in the ischemic core (IC) and penumbra (IP). Results Ifenprodil pretreatment significantly decreased the cerebral infarct size and neurological scores in group IF as compared with group I/R. In group I/R the iNOS activity was increased compared with group S.The iNOS activity and NO content were significantly lower in IP than in IC in group IR and IF. The TUNEL-positive cells were also mainly confined to IP. Compared with group I/R, in group IF the iNOS protein expression was significantly down-regulated in IC and IP and the iNOS activity and NO content in IC and IP were suppressed and TUNEL-positive cells were significantly reduced in IP. Conclusion Ifenprodil pretreatment has protective effect against cerebral I/R injury by inhibiting iNOS protein expression in IP, suppressing iNOS activity and NO content and reducing apoptosis.